Word of mouth (WOM) is a phenomenon that has received much attention in practical and academic applications in recent times. Especially, Many companies have recognized its importance and tried to generate positive WOM. These attempts have been mainly focused on increasing customer satisfaction, improving customer loyalty and generating positive WOMabout a company or product. It is therefore important to investigate the explanation of WOM occurrences. This study explains the reason why WOM has been occurred with a need for self-presentation of customers. Self-presentation(SP) is the use of behavior to communicate some information about oneself to others. That is, self-presentation is to express personal thought, feeling, and emotion toward himself/herself; thus, the consumption and purchase activity of goods is also one type of self-presentation. This study classified self-presentation into self-constructive SP and audience pleasing SP. Self-constructive SP is to express himself/herself according to his/her inner ideal, while audience pleasing SP means an effort to have a good image in the public audience. Also, the study considers intrinsic motivation and extrinsic motivation as the mediators of self-presentation and WOM intention, and classified and took a look into these motivations into cognitive dimension and affective dimension, respectively. As the intrinsic motivation of a cognitive aspect, the study classified it as altruism. Meanwhile the study classified the intrinsic motivation of an emotional aspect as enjoyment. Then, the study classified the cognitive aspect of extrinsic motivation as reward, and the emotional aspect as recognition by others. In addition, this study examines the moderating role of product type(hedonic vs. utilitarian)is examined in the relationship between intrinsic/extrinsic motivation and WOM to identify the difference of the path coefficients in the cognitive and affective dimensions of intrinsic and extrinsic motivation. The key findings are as follows. First, self constructive SP has a positive effects on the cognitive and affective dimensions of intrinsic motivation; respectively altruism and enjoyment. Audience pleasing SP has not a significant effect on cognitive dimension of extrinsic motivation (monetary reward), while has a positive effect on affective dimension of extrinsic motivation (recognition). Second, the cognitive and affective dimensions of intrinsic motivation have a positive effect on WOM. The affective dimension of extrinsic motivation has a positive effect on WOM, while cognitive dimension of extrinsic motivation has not a significant effect. Third, the effects of intrinsic and extrinsic motivations on WOM show that the effect has different results by product type. The effect of cognitive dimension of intrinsic motivation on WOM is higher for utilitarian product than hedonic product while the effect of affective dimension of intrinsic motivation on WOM is higher for hedonic product than utilitarian product. This study provides more complete understanding of WOM theoretically. Key theoretical implications of the study are as follows. This study deals with the underlying process of WOM from the viewpoint of the sender while many studies about motivation of WOM are anecdotal evidence or conceptual research. This study has proposed the theoretical process of WOM and investigated it empirically: ‘self-presentation→intrinsic/extrinsic motivation→WOM’. This study has several practical implications. For the purpose of the increasing the WOM,companies should emphasize not simply reward but the enjoyment and altruistic motivation. Additionally, WOM is able to increase by stimulating enjoyment with WOM itself for the hedonic products, whereas, it is effective to emphasize altruism for the utilitarian products.